feat: support JSON data type (#135)

* feat: support JSON data type

* fix type

* bug fixes

* erase excess test override

* erase excess override

* fix errors

Co-authored-by: larkee <31196561+larkee@users.noreply.github.com>
Co-authored-by: skuruppu <skuruppu@google.com>

google/cloud/sqlalchemy_spanner/requirements.py

@@ -17,6 +17,10 @@
 
 
 class Requirements(SuiteRequirements):  # pragma: no cover
+    @property
+    def json_type(self):
+        return exclusions.open()
+
     @property
     def computed_columns(self):
         return exclusions.open()

google/cloud/sqlalchemy_spanner/sqlalchemy_spanner.py

@@ -34,9 +34,13 @@
     GenericTypeCompiler,
     IdentifierPreparer,
     SQLCompiler,
+    OPERATORS,
     RESERVED_WORDS,
 )
+from sqlalchemy.sql.default_comparator import operator_lookup
+from sqlalchemy.sql.operators import json_getitem_op
 
+from google.cloud.spanner_v1.data_types import JsonObject
 from google.cloud import spanner_dbapi
 from google.cloud.sqlalchemy_spanner._opentelemetry_tracing import trace_call
 
@@ -47,6 +51,10 @@ def reset_connection(dbapi_conn, connection_record):
     dbapi_conn.connection.staleness = None
 
 
+# register a method to get a single value of a JSON object
+OPERATORS[json_getitem_op] = operator_lookup["json_getitem_op"]
+
+
 # Spanner-to-SQLAlchemy types map
 _type_map = {
     "BOOL": types.Boolean,
@@ -60,8 +68,10 @@ def reset_connection(dbapi_conn, connection_record):
     "TIME": types.TIME,
     "TIMESTAMP": types.TIMESTAMP,
     "ARRAY": types.ARRAY,
+    "JSON": types.JSON,
 }
 
+
 _type_map_inv = {
     types.Boolean: "BOOL",
     types.BINARY: "BYTES(MAX)",
@@ -210,6 +220,53 @@ def visit_like_op_binary(self, binary, operator, **kw):
             binary.right._compiler_dispatch(self, **kw),
         )
 
+    def _generate_generic_binary(self, binary, opstring, eager_grouping=False, **kw):
+        """The method is overriden to process JSON data type cases."""
+        _in_binary = kw.get("_in_binary", False)
+
+        kw["_in_binary"] = True
+
+        if isinstance(opstring, str):
+            text = (
+                binary.left._compiler_dispatch(
+                    self, eager_grouping=eager_grouping, **kw
+                )
+                + opstring
+                + binary.right._compiler_dispatch(
+                    self, eager_grouping=eager_grouping, **kw
+                )
+            )
+            if _in_binary and eager_grouping:
+                text = "(%s)" % text
+        else:
+            # got JSON data
+            right_value = getattr(
+                binary.right, "value", None
+            ) or binary.right._compiler_dispatch(
+                self, eager_grouping=eager_grouping, **kw
+            )
+
+            text = (
+                binary.left._compiler_dispatch(
+                    self, eager_grouping=eager_grouping, **kw
+                )
+                + """, "$."""
+                + str(right_value)
+                + '"'
+            )
+            text = "JSON_VALUE(%s)" % text
+
+        return text
+
+    def visit_json_path_getitem_op_binary(self, binary, operator, **kw):
+        """Build a JSON_VALUE() function call."""
+        expr = """JSON_VALUE(%s, "$.%s")"""
+
+        return expr % (
+            self.process(binary.left, **kw),
+            self.process(binary.right, **kw),
+        )
+
     def render_literal_value(self, value, type_):
         """Render the value of a bind parameter as a quoted literal.
 
@@ -404,6 +461,9 @@ def visit_NUMERIC(self, type_, **kw):
     def visit_BIGINT(self, type_, **kw):
         return "INT64"
 
+    def visit_JSON(self, type_, **kw):
+        return "JSON"
+
 
 class SpannerDialect(DefaultDialect):
     """Cloud Spanner dialect.
@@ -434,6 +494,8 @@ class SpannerDialect(DefaultDialect):
     statement_compiler = SpannerSQLCompiler
     type_compiler = SpannerTypeCompiler
     execution_ctx_cls = SpannerExecutionContext
+    _json_serializer = JsonObject
+    _json_deserializer = JsonObject
 
     @classmethod
     def dbapi(cls):

test/test_suite.py

@@ -20,6 +20,7 @@
 import os
 import pkg_resources
 import pytest
+import random
 import unittest
 from unittest import mock
 
@@ -61,7 +62,6 @@
 )
 
 from google.api_core.datetime_helpers import DatetimeWithNanoseconds
-
 from google.cloud import spanner_dbapi
 
 from sqlalchemy.testing.suite.test_cte import *  # noqa: F401, F403
@@ -98,15 +98,17 @@
 )
 from sqlalchemy.testing.suite.test_results import RowFetchTest as _RowFetchTest
 from sqlalchemy.testing.suite.test_types import (  # noqa: F401, F403
+    _DateFixture as _DateFixtureTest,
+    _LiteralRoundTripFixture,
+    _UnicodeFixture as _UnicodeFixtureTest,
     BooleanTest as _BooleanTest,
     DateTest as _DateTest,
-    _DateFixture as _DateFixtureTest,
     DateTimeHistoricTest,
     DateTimeCoercedToDateTimeTest as _DateTimeCoercedToDateTimeTest,
     DateTimeMicrosecondsTest as _DateTimeMicrosecondsTest,
     DateTimeTest as _DateTimeTest,
     IntegerTest as _IntegerTest,
-    _LiteralRoundTripFixture,
+    JSONTest as _JSONTest,
     NumericTest as _NumericTest,
     StringTest as _StringTest,
     TextTest as _TextTest,
@@ -115,7 +117,6 @@
     TimestampMicrosecondsTest,
     UnicodeVarcharTest as _UnicodeVarcharTest,
     UnicodeTextTest as _UnicodeTextTest,
-    _UnicodeFixture as _UnicodeFixtureTest,
 )
 from test._helpers import get_db_url
 
@@ -1751,3 +1752,128 @@ def test_get_column_returns_computed(self):
         is_true("computed" in compData)
         is_true("sqltext" in compData["computed"])
         eq_(self.normalize(compData["computed"]["sqltext"]), "normal+42")
+
+
+@pytest.mark.skipif(
+    bool(os.environ.get("SPANNER_EMULATOR_HOST")), reason="Skipped on emulator"
+)
+class JSONTest(_JSONTest):
+    @pytest.mark.skip("Values without keys are not supported.")
+    def test_single_element_round_trip(self, element):
+        pass
+
+    def _test_round_trip(self, data_element):
+        data_table = self.tables.data_table
+
+        config.db.execute(
+            data_table.insert(),
+            {"id": random.randint(1, 100000000), "name": "row1", "data": data_element},
+        )
+
+        row = config.db.execute(select([data_table.c.data])).first()
+
+        eq_(row, (data_element,))
+
+    def test_unicode_round_trip(self):
+        # note we include Unicode supplementary characters as well
+        with config.db.connect() as conn:
+            conn.execute(
+                self.tables.data_table.insert(),
+                {
+                    "id": random.randint(1, 100000000),
+                    "name": "r1",
+                    "data": {
+                        util.u("réve🐍 illé"): util.u("réve🐍 illé"),
+                        "data": {"k1": util.u("drôl🐍e")},
+                    },
+                },
+            )
+
+            eq_(
+                conn.scalar(select([self.tables.data_table.c.data])),
+                {
+                    util.u("réve🐍 illé"): util.u("réve🐍 illé"),
+                    "data": {"k1": util.u("drôl🐍e")},
+                },
+            )
+
+    @pytest.mark.skip("Parameterized types are not supported.")
+    def test_eval_none_flag_orm(self):
+        pass
+
+    @pytest.mark.skip(
+        "Spanner JSON_VALUE() always returns STRING,"
+        "thus, this test case can't be executed."
+    )
+    def test_index_typed_comparison(self):
+        pass
+
+    @pytest.mark.skip(
+        "Spanner JSON_VALUE() always returns STRING,"
+        "thus, this test case can't be executed."
+    )
+    def test_path_typed_comparison(self):
+        pass
+
+    @pytest.mark.skip("Custom JSON de-/serializers are not supported.")
+    def test_round_trip_custom_json(self):
+        pass
+
+    def _index_fixtures(fn):
+        fn = testing.combinations(
+            ("boolean", True),
+            ("boolean", False),
+            ("boolean", None),
+            ("string", "some string"),
+            ("string", None),
+            ("integer", 15),
+            ("integer", 1),
+            ("integer", 0),
+            ("integer", None),
+            ("float", 28.5),
+            ("float", None),
+            id_="sa",
+        )(fn)
+        return fn
+
+    @_index_fixtures
+    def test_index_typed_access(self, datatype, value):
+        data_table = self.tables.data_table
+        data_element = {"key1": value}
+        with config.db.connect() as conn:
+            conn.execute(
+                data_table.insert(),
+                {
+                    "id": random.randint(1, 100000000),
+                    "name": "row1",
+                    "data": data_element,
+                    "nulldata": data_element,
+                },
+            )
+
+            expr = data_table.c.data["key1"]
+            expr = getattr(expr, "as_%s" % datatype)()
+
+            roundtrip = conn.scalar(select([expr]))
+            if roundtrip in ("true", "false", None):
+                roundtrip = str(roundtrip).capitalize()
+
+            eq_(str(roundtrip), str(value))
+
+    @pytest.mark.skip(
+        "Spanner doesn't support type casts inside JSON_VALUE() function."
+    )
+    def test_round_trip_json_null_as_json_null(self):
+        pass
+
+    @pytest.mark.skip(
+        "Spanner doesn't support type casts inside JSON_VALUE() function."
+    )
+    def test_round_trip_none_as_json_null(self):
+        pass
+
+    @pytest.mark.skip(
+        "Spanner doesn't support type casts inside JSON_VALUE() function."
+    )
+    def test_round_trip_none_as_sql_null(self):
+        pass